Apparatus for force application

ABSTRACT

A frame has a slidably mounted skid assembly thereon with extensible and retractable cylinder means secured to the skid and to an object to which force is to be applied. The frame has sequentially spaced block means interengageable with selective dog means on the skid to restrict movement of the skid in either of two directions upon actuation of the cylinder means. The frame is carried in a mobile support attachable to various types of prime movers.

United States Patent [111 3,567,044

5/1960 Langen........................ 167 4/1962 Roussel 498 4/ 1965 Postlewaite 076 3/1966 Huffet al.... 077 3/1966 Huffet a1. 7/1867 Critteden Primary Examiner-Gerald M. Forlenza [72] Inventor Bobby J. Travis 345 Mayhaw, Vidor, Tex. 77662 [21} Appl. No. 756,920 [22] Filed Sept. 3, 1968 [45] Patented Mar. 2, 1971 r e m m H 0 nM mc FM ,G mm m a R I V. MM .mw m AA N O I. T A C m P P A E mm 0F .m mm SD U5 Tl As m PC A7 M U ABSTRACT: A frame has a slidably mounted skid assembly thereon with extensible and retractable cylinder means [51] Int. B66f 1/00 [50] Field 214/1 (P),

secured to the skid and to an object to which force is to be ap' plied. The frame has sequentially spaced block means i 294/86 (C6) 78 (A) terengageable with selective dog means on the skid to restrict movement of the skid in either of two directions u tion of the cylinder means.

References Cited UNITED STATES PATENTS 2,412,488 12/1946 pon actua- The frame is carried in a mobile support attachable to various types of prime movers.

' PATENTEU MAR 2 ran SHEET 1 or 7 OBBY TRA ATTORNEY PATENTE DHAR 2m: 5 104 :SHEET 3 HF? BOBBY ITEM/us PM AmQmm ATTORNEY PATENYTED'IMAR 213w sum 6 OF 7 r INVENTOR 5055* I. TBAVl; BY QM mmmm ATTORNEY APPARATUS FOR FORCE APPLICATION BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to the application of linear force for the insertion or removal of a first item with respect to a second item,:particularly when the first item is tightly engaged within the second item. An environment of particular adaptability concerns the utilization of the apparatus hereof in the placement and removal of tube bundlesin-heat exchange apparatus of the type employed in-the chemical and petroleum industries. I

2. Statement of the Prior Art A problem commonly encountered in industry, and particularly in the chemical and petroleum processing field, concerns the handlingof heat exchange tube bundles, which comprise tubular shells into which cylindrically arranged groups or bundles of tubes are placed. Periodically it is necessary. that these tube bundlesbe removed from their shells forIcleaning and/or repair. The bundles are normally horizontally arranged, and may be located at substantial height with respect to the ground. Due to the nature of the functions performed,.the bundles are at times subjected to chemical deposit of contaminates rendering them very difficult to remove, therefore requiring a substantial force to remove thebundle from, its shell.

Conventional removal proceduresinvolve pulling the'bundle from the shell with a cable attached to a poweredwinch, and the connection of further support cables, suspended from an overhead boom, to the bundle asit slides out of the shell. This method has been criticizedfrom thestandpoint of the continuously present hazard of winch line breakage, the necessity for multiple operators, and the fact that this method does not provide effective means for replacement of the bundle within the shell after servicing.

In prior attempts to overcome these problems, various types of apparatus have been developed, as represented in the following prior U.S. Pat. Nos.: 1,040,252, Pennypacker, Oct. 1, 1912; 1,666,286, Hollowell, Apr. 17, 1928; 1,760,989, Lewis, Jun. 3, 1930; 2,764,806, Woodward, Oct.'2, l956;'3,048,280,

Huff et al., Aug. 7, 1962; 3,126,103, Postlewaite et al.,Mar.

24, 1964; 3,180,498, Postlewaite, -Apr. 27, 1965; 3,239,077, Huff et al., Mar. 9, 1966; and 3,257,00lflostlewaite et 211., Jun. 21, 1966.

The foregoing arrangements comprise improvements on the generally accepted winch and cable arrangements described above. However, each of the types of apparatus represented in giving rise to a high degree of damage to the bundle in these recurring maintenance operations.

SUMMARY OFTl-IE INVENTION The present. invention provides means forthe placement and removal of a bulky article positioned within another article, the apparatus hereof including a structure arranged to support the bulky article during placement and removal, which includes a balanced application of force operative to at ficiently apply the force at the desired location, and onewhich avoids the possibility of damage to the extracted or replaced article.

Objectives of this invention include theprovision of a tube bundle extractor of simplified design, and extractors which have a high degree of safety in operation,which require only a minimum crewfor effective operation, and which are readily adapted to transport with and cooperation with existing prime movers.

A further and principle objective of this invention resides in the provision of a controlled sequence, indexed withdrawal andiplacement means for tube bundles, the mechanism hereof being coactive with the supporting frame of the apparatus in achieving the force application function of the device.

Still further advantages of the invention include the fact that the components of the apparatus are adapted for fabrication from standard and available stock or from available assemblies, in large part, thereby reducing the expense of original manufacture and following maintenance procedures.

Other and further objects and advantages of this invention will become apparent to those skilled in the art from a consideration of the followingspecification when read in conjunction with the annexed drawings.

BRIEF DESCRIPTION OF THEDRAWINGS FIG. 1 is a perspective view ofa first form. of apparatus constructed and assembled in accordance with the teachings of.

this invention;

.FIG. 2 is a top plan view, partially in cross section, ofthe apparatus of FIG. 1;

FIG. 3 is a side elevational view, also partially in cross section;

FIG. 4 is a front elevational view;

FIG. 5 is a. perspective view disclosing details of the undersideof the skid assembly forming an important component of the invention;

FIG. 6 is an enlargedsectional view taken substantially on the line 6-6 of FIG. 3, looking in the direction of the arrows;

FIG. 7 is a disassembled perspective view of a portion of movable roller means hereof;

FIG. 8 is another transverse cross-sectional view taken substantially on the plane of the line 8-8 of FIG. 3, looking in the direction of the arrows;

FIG. 9 is a sectional view of details on an enlarged scale, on line 9-9 of FIG. 8, looking in the direction of the arrows, and showing the components in one operating position;

FIG. 10 is a view similar toFIG. 9, but showing the elements in a reversed operating position;

FIG. 11 is a foreshortened side view, partially in cross section, of a modification of the construction and assembly of the apparatus of this invention;

FIG. 12 is a sectional view. on.the line 12-12 of FIG. 11, looking in the direction of the arrows;

FIG. 13 is an .enlargeddetailed sectional view on line 13-13 .ofFIG. 12;

FIG. 14 is an enlarged elevational view of a shell engaging clamp means of the modified form of the invention; and

FIG. 15 is a partial front view of the clamp means as viewed from line 15-15 of F1G.'14.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Initial reference is.made.to FIGS. 1 through 10 of the drawings, wherein a firstform of the instant invention is characterized by general reference numeral 20. The structural concepts of this invention are applicable in those situations wherein the exertion of a linear force for-extraction of an elementpositioned within another element is desirable ornecessary; the illustrated environment of use herein disclosed being that of that portion of a heat exchange assembly whichcomprises a tubular shield 22 having an open end with a surroundingflange 24. In the normal operation of the heat exchange apparatus, a cylindrically arranged bundle26 of tubes is engaged within the shell/The tubes are held in said position by a plurality of perforated plates or baffles 28, and byan end con- .nector 30. The bundle 26 isslidably disposed in the shell, but in use often becomes tightly lodged due to the build up of chemical deposits, and the like. Thus, when removal for clean- .ing and other servicing is necessary, the bundle must be subjected to substantial linear force. Moreover, the replacement of the bundle requires. an opposite application. of force in order to reseatthe bundle in its shell.

Apparatus of the present invention includes, as a major structural component, an elongated base frame structure 32 of heavy metallic construction. The frame structure 32 includes side frame members 34 and 36 each composed of two spaced apart sidewalls 38, 40, and a top wall 42 with an inward, rebent flange having a slide surface 44. The surfaces 44 of the respective side members are angled toward one another.

As best shown in FIGS. 1 and 3, the base frame side members 34 and 36 are interconnected by transverse structural members 46 spanning the distance therebetween at longitudinally spaced positions. The members 46 each include a horizontal top 48, the tops 48 being located in mutual horizontal alignment in a plane below that of the top walls 42 of the side members, and the members further include lateral skirts 50, 52. Extending across the tops 48 of the transverse members 46 and secured to each of them is an intermediate support beam 54 formed of heavy channel stock. The intermediate support beam is substantially coextensive in length with the side frame members and is medially arranged with respect thereto. Affixed to the tops 48 on either side of the central beam 54 are a plurality of block means 56, serving a function appearing in detail below. The intermediate beam 54, and the blocks 56, are disposed in a depressed horizontal plane relative to the side beams.

The entire base frame structure is mounted in a cradle assembly 58 which includes lateral outrigger members 60, 62 with I beams 64 connecting their ends to the respective outer sidewalls 40, and braces 66 as required by weight functions spanning the distance between the sidewalls and the outrigger members. Pairs of connection ears 68 are secured on the upper sides of the outriggers 60 and 62 and elongated lift bars 70 are pivoted between the ears of each pair at their proximal ends 72. The distal ends 74 of the lift bars are slotted, at 76, and bolts 78 extend therethrough and are slidable within the slots. The bolts 78 comprise portions of a yoke 80 having arms 82 and 84 joined at their ends remote from the bolts. As

best shown in FIG. 1, there are four such yokes 80, joined in 7 pairs to crossbeams 86, 88, which are interconnected by a longitudinal beam 90. A traveling hoist connection 92 is mounted on the beam 90 and includes an adjustment screw 94 and a pickup ring 96. The adjustment screw permits changing the center of gravity of the overall apparatus in accordance with weight functions of the article to be supported thereon. The ring 96 is engageable with transport apparatus such as a crane, having a hook 98, or other types of available prime movers. The maneuverability of the yoke with respect to the lift bars, and the fact that the bars are themselves pivotal with respect to the frame, increases the adaptability of positioning of the apparatus, and permits movement of extracted tube bundles in areas where only small movements are practically possible.

For purposes of description, the base frame structure has a forward end, identified by reference numeral 100, and an opposite trailing end 102. A plate 104 is mounted across the leading end 100, and has a central concave portion approximating the form of the bundle 26 at that point. A plurality of shafts 106 having external screwthreads project longitudinally forward of the plate, and the shafts have sleeves 108 thereon with upstanding clamp plates 110. Clamping nuts 112 are threadedly engaged on the shafts. As shown in FIGS. 2 and 3, the shafts extend forwardly of the flange 24 of the shell 22, with the flange abutting the plate 104. The clamp plates 110 then are engaged against the opposite sides of the flange, and the nuts 112 turn in a suitable direction to effect a secure connection between the leading end of the support, and the bundle shell. This relationship of the support to the shell is effected as an initial step in either an assembly or disassembly operation involving the apparatus and the bundle with respect to its shell.

Referring to FIG. of the drawings, another major component of the invention apparatus therein in shown, comprising a skid assembly 114. The assembly 114 includes a top plate 116 of substantially flat, rectangular form, dimensioned to span the distance between the top wall 42 of the side frame members, and having depending side flanges 118 and 120. Front and rear plates 122, 124 also depend from the plate 116, and each has a deep rectangular central portion 126 with vertical side edges, outwardly flared intermediate slide edges 128 corresponding in angularity to the slide surfaces 44 of the side members, and horizontal lateral edges 130 coextensive in depth with the side flanges 118 and 120. Inwardly from the side flanges a distance generally equal to the width of the top walls 42 of the side members are interior channel members 132, 134 having transversely arranged, rotatable rollers 136 which, as shown in FIG. 8, rest on the top walls 42 of the side members. The slide members further include inside vertical walls 138, 140 having side elements 142, 144 thereon reinforced by gussets 146. The side plates extend under the slide surface 44 of the rebent flange of the side members. Thus, with the rollers 134, 136 engaged on the top walls 42, the slide edges 128 are closely spaced from the slide surface 44 and the elements are retained in this position regardless of upward displacement forces by the elements 142, and 144.

The plate 116 has a central slot 146 extending substantially its full length, with inner walls 148 and 150 on either side thereof. The said walls are positioned above the intermediate beam 54 and are connected at intervals by crossbars 152 which also extend laterally of the walls 138 and 140.

The structure between the pairs of walls 138 and 148, and 140 and 150, comprises a subject of great importance to the invention in that it provides means for the distribution of balanced forces to the structure. This structure, and the operational characteristics thereof, is best viewed in FIGS. 9 and 10 of the drawings. It will there be observed that the bars 152 have outer, tubular sleeves 154 thereabout, and that the sleeves are movable with respect to the bars. Levers 156 and 158 are fixed to each of the sleeves and are connected by springs 160, 162, respectively, to the top plate 116. The springs constantly urge the levers upwardly in the direction of the plate. The outer ends of the levers are each pivotally connected to handles 164, 166 having right angular actuating portions 168, 170. The handles extend through openings formed in the top wall 116 and the portions 168 and 170 are located above the plate. Each of the handles has a transverse cross piece 172, 174 thereon which is passed through an opening provided therefor in the top wall, as appears below. Between the aforesaid pairs of walls 138-148 and 140-150 the sleeves 154 each have pairs of arms 176, 178 thereon. The pairs of arms are each connected together by bars 180 which, with the lever 176 in raised position, are longitudinally aligned with the block means 56. As appears below in the description of operation of this invention, the aforesaid structure comprises an extensible and retractable dog means engageable with the blocks in the sequential extraction or placement of a tube bundle within its shell.

Referring once again to FIGS. 2 and 8 of the drawings, it will there be noted that a hydraulic cylinder 182 is mounted on the top plate 116 over its central slot 146, between blocks 184, 186. The cylinder has an extensible and retractable rod 188 with a clevis 190 on its outer end. The clevis has a connector plate 192 thereon. The cylinder 182 has the usual hydraulic fittings and conduits, the disclosure of which has been omitted from the drawings for clarity of illustration. The plate 192 is clamped, by changeable fastening means 194, to the exposed end of a tube bundle, and the fastening means may extend completely through the tube bundle to a connection on the opposite side thereof, which arrangement avoids damage to the bundle occasioned by pulling on one end only thereof.

In order to maintain the base frame in level relationship to the shell during operation, supplementary leveling means is supplied. In FIG. 8, the means is seen to comprise lateral wings 196, 198 on the outer walls 40 of the frame side members. The wings have vertical openings therebetween receiving elongated leveling rods 200, 202 with threaded nuts 204, 206 at their lower ends for height adjustment. The upper ends 208, 210 are of right angular relationship to the vertical rods, and extend through the shell flange 24 on either side. The rods are connected by suitable fasteners on the opposite sides thereof.

The tube bundles contemplated in this example of the invention areof substantial weight, often greatly exceeding the weight of the apparatus. Inorder to avoid damage to the bundles and to ensure smooth operation during extraction or replacement, it is desirable to interpose movable roller means between the bundles and the base frame. Such means is generally identified inthe drawing by reference numeral 212 and is best shown in FIGS. 6 and 7 thereof. The means 212 include a channel member 214 having a pair of axle support members 216, 218 arranged centrally thereof. Dual transverse rollers 220 are journaled on axles 222 mounted between the axle support, members, and the rollers ride on the intermediate support beam'54. Angle plates 224,, 226 are secured to the ends of the channel member 214 and have extensions228 and 230. respectively. Gusset plates 232 are secured to the chanriel members and to the angle plates. The extensions 228,230 each have two spaced apart roller housing brackets 234, 2 36 thereon with rollers 238, 240 thereon engaged on the tops 42 of the side frame members. Disposed between the housing brackets of each pair thereof is an upstanding block 242 having a threaded bore therein with a bolt 244 engaged in its threads. The bolts 244 contact stepped,,load bearing blocks 246 which have angular upper surfaces 248. As shown in FIG. 6, a supplementary bearing block 250:;may be used to prop support bundles of lesser dimension then is provided for by the adjustment of the blocks 246, where required.

The operation of the invention, either for extraction or replacement of the bundles from or to a shell involves, initially, the connection of the base frame to the shell in the manner heretofore indicated. FIG. 90f the drawing indicates the position of the dog means with respect to the block whena bundle is in the process of extraction from its shell. It .will there be observed that the lever 158 has been depressed by inward pressure applied to its handle 166, the crosspiece 174 being engaged under theplate 1.16 thereby holding the bar 180 inan elevated position out of possible contact with the transverse blocks 56. The lever 176,is however in lowered position by virtue of the disengagement of thecrosspiece 1.72 permitting the spring 160 to elevate the lever 156. With the elements in this position, the rod 188 is extended from the cylinder182 to a position wherein the plate 192 contacts the tr be bundle. It is there connected tothe bundle in the manner described above, and upon such connection, the fluid is pumped into the cylinder on its rod side of thewpiston, causing the cylinder to exert a force on the bundle. The skid assembly is however held stationary by. the, engageddog means onthe transverse blocks, which results in transmissionofanlopposite force to the, shell via the blocks and the main structure. The bundle is therefore extracted to the stroke length of the cylinder. At this position, the fluid is applied to the opposite or piston end of the cylinder, and inasmuch as the .bundleisof substantially greater weight than the cylinder and skid, the frictional forces created are exerted thereagainst causing the skid to move back on the main structure until the next set of transverse blocks. 56 are engaged by the spring biased crosspiece 180. The direction of fluid flow. is then reversed again causing it to contact the rod end of the cylinder and the bundle is therefore extracted another stroke length. This procedure is repeated until the bundle is extracted from the shell. It will be appreciated that the bundle, throughout this operation, is connected not only to the plate 192, but additionally rests on the movable roller means 212 Insertion of the bundle involves initial positioning of the skid assembly at the trailing end of the main structure, remote from the shell. The elements of the skid assembly are then changed to the FIG. 10 position, wherein the lever 158 is elevated and the lever 156 depressed, causing an opposite engagement of the crosspieces 180 of the former assembly and disengagement of the crosspiece 180 .of. the former assembly and disengagement of the crosspiece 180 of the latter. The bundle is placed onthe structure-by a crane or otheravailable transport means, and is secured to the cylinder plate in the same manner as described aboveyfor extraction. The main structure is then secured to the exchange shell flange by the employment of the clamping means and leveling rods described above. Assuming prealignment of the bundle with the shell, fluid is applied to the piston end of the cylinder, forcing the bundle into the -shell at stroke length steps. Reversing of the fluid to the rod endof the cylinder causes the cylinder skid to move toward the bundle until the next set of cross blocks 56 are engaged. Thus, the bundle and skid are indexed forwardly until thebundle is suitably seated within the shell.

FIGS. ll through l5 illustrate a second embodiment of the invention. Reference numerals for this form of the invention correspond, where applicable, to those applied to the basic form of the invention, the letter a being appended for purposes of distinction in the second form-of the invention. The modification is generally identified by reference numeral 20a, andis shown, in the nonlimiting environment hereof, in use in the placement. or extraction of a bundle 26a of tubes froma heat exchange shell 22a with a flange 24a. The bundle 26a has a forward end connector 30a. The base frame structure 32a,of the modified form of the invention comprises opposing, inwardly facing side members 300, 302 ofchannel stock, interconnected by transverse members 460 spanningthe distance therebetween at laterally spaced positions. The tops 48a of the members 46aare horizontally aligned, ina plane below that of the upper arms 3.04, 306 of the channel members, and the tops have block means 56a extended thereacross.

Affixed to the frame upper arms 304 and 306 are longitudinally extending pipe members 308 and 310. The frame 320 has a leading end a, and an opposite trailing end. InFlGS. 11 and 12 it will'be noted that angularly secured support bars 312 and 314 of a carriage assembly. hereof extend outwardly from the frame at spaced locations. The bars at each side of the frame are interconnected by longitudinal bars 316 having rotatable sleeves 318 at the respective ends thereof. Each of the sleeves has an ear 320 connected by heavy duty cables 322 to cars 324 on an overhead hoist bar 326.

A skid assembly 114a ofthe modifiedform of the invention includes plate means 116a composed of top plates 328 and bottom plates 330 at each end of the assembly. The said plates have horizontal, shallow depressions 332 adjacent their marginal side edges whereby they fit over and slidably engage the pipe members 308. and 310 and they are further connected to one another by vertical axial bushings 334 which are elon' gated and extend substantially the full length of the skid assembly interconnecting the plates at either end thereof. A forward axle 336 extends through the bushings at the leading end of theskid and carries a plurality of levers 338, interconnected by a cross rod ,340. The levers have flat forward faces 342, which normally gravitate to a vertical position, and has inclined rear faces 344.,Each has a lateral lug 346 (FIG. 13) adapted for engagement in a matching detent 348 formed in the adjacent one of the bushings upon rotation of the lever to a location where the lug and detent are coaligned. Thus, the levers may be placed in the depending position of FIG. 13, or alternatively in an upright, horizontal storage position. In like manner, a rear axle 350 extends through the bushings at the trailing end of the skid, and has oppositely arranged levers 35'2 pivoted thereon. The levers 352 are interconnected by cross rods 354 and each has aflat face 356 and an angle face 358- the trailing end levers being arranged oppositely with respect to the arrangement of the levers 338. In FIG. 11, the trailing end levers are shown in elevated position, with the detent means thereof in the retaining position.

Mounted between pressure blocks 184a, 186a is the tube portion 182a of a hydraulic cylinder assembly which further includes an extensible and retractable trod 188a. The rod has a clevis 190a on itsdistal end, connectedtoa plate 192a which is the means for attachment of the rod to the bundle during placement andextraction operations.

FIGS. 14 and 15 show an improved means 360 for attachment of the leading .end 100a of the frame to the shell flange 24a. Such means, which is located at each sideof the frame, comprises side plates 362, mounted in outwardly spaced relation to the side frame members 300 and 302 by flanges 364, 366, thereby defining a slot space between the side plates and frame members. Slidably disposed in the slide spaces are clamp plates 368, having trailing ends 370 connected to the extensible portion 372 of a small hydraulic cylinder 374. As seen in the drawing, the plate 368 has a window 376 formed therein permitting the connection of the portion 372 to the end 370, and permitting extension and retraction of the cylinder portion to its stroke length. The opposite end of the clamp plate has an upstanding arm 378 which effectively clamps behind the shell flange 24a to lock the base frame of the improved form of the invention to the shell flange. The manner of operation of this feature of the invention is best indicated in FIGS. 11 and 14, where it will be observed that the clamp plate when extended by action of the cylinder may be fitted behind the flange. Actuation of the cylinder causes movement of the base frame forwardly against the flange, due to the weight differential involved, thereby clamping the flange between the arm and the end of the frame and effecting a secure connection therebetween.

Leveling means for this form of the invention comprises lateral wings 196a, 198a at either side of the frame. Leveling rods 200a (which may have a turn buckle therein as shown in FIG. 11 for ease of connection) extend upwardly from a connection between the wings and engage the shell flange in the same manner that the rods 200 of the first form of the invention engage the flange therein.

Operation of the second form of the invention is much the same as that described above with respect to the first form, involving the sequential indexing of the bundle inwardly and outwardly by extension and retraction of the rod 188a of the cylinder 182a through the opposite application of fluid pressure on either side of the piston means of the hydraulic cylinder. In this case, the interaction 'between the depending levers comprising the dog means with the cross blocks 56a is a function of the group of levers selected. That is, where the extraction of the bundle is to be effected, the forward levers 338 are placed in the depending position shown in FIG. 11 and the trailing end levers 352 are suspended in the up position wherein they do not contact the blocks. The opposite is true where replacement of the bundle is to be effected.

' In the functional characteristics, each of the above forms of this invention centers on the balancing of force which permits the employment of a relatively lightweight, mobile frame applying forces in the range many times its own weight to an article which also substantially exceeds the weight of the framework. It is here to be observed that the trackway on which the skid assembly rides is disposed at an intermediate location between the centerline ofthrust of the hydraulic cylinder and the dog means of the framework. It is against this intermediate force position that the major weight of resistance is encountered, and by virtue of the fact that the applied force is equalized on either side (e.g., at the dog means and at the centerline of the cylinder rod) the aforesaid balance of force is effectively achieved. 7

Having described and illustrated two forms of the invention in some detail, it will be understood that this description and illustration have been offered only by way of example, and that the invention is to be limited in scope only by the appended claims.

Iclaim:

1. Means for placement and extraction of an element engaged within a shell and longitudinally slidably therefrom, the means comprising:

an elongated frame having side members and having spaced apart transverse members spanning the side members;

a skid, including plate means slidably engaged on the side members above the transverse members;

block means on the transverse members;

cylinder means, including a fixed actuating tube on the plate and a rod extendible and retractable from the tube, the rod being connected to the elements;

two sets of dog means secured to the plate on the skid, the

sets being individually movable from storage ositions to use positions, each set being engageable wit the block means when in its use positions;.and

means securing the frame to the shell whereby extension of the rod causes movement of the skid and the attached element outwardly from the shell when a first selected set of dogs is in use position, and causes movement of the elements into the shell when the other set of dogs is in use position.

2. The invention of claim 1, wherein: the dogs contact the block means in end-to-end sequence.

3. The invention of claim 2, wherein: the means securing the frame to the shell comprises clamping plates and hydraulic cylinder means controlling the clamping plates.

4. The invention of claim 3, and: leveling rods extending upwardly from the frame and secured to the shell.

5. Apparatus for removal and replacement of tube bundles in heat exchange assemblies, the tube bundles having a projecting portion and the assembly including a shell section, the apparatus comprising:

a base frame structure including elongated side support beams, and intermediate support beams, and transverse structural members interconnecting the side support beams and the intermediate support beam;

the side support beam occupying a horizontal plane elevated with respect to a horizontal plane occupied by the intermediate support beam;

block means on the transverse structural members;

a skid assembly, including a plate member spanning the frame structure and having side rollers engaged on the side support beams, the platemember having an assembly depending therefrom to straddle the intermediate support beams;

retractable and extendible dog means on the assembly, ex-

tending from the plate member, engageable with the block means when in extended position to prevent movement of the skid assembly in direction;

extendible and retractable cylinder means having a fixed portion secured on the plate member and having a rod portion operatively connected thereto, the rod portion having means on one end for connection to the projecting portion of the bundle;

clamping means securing the base frame structure to the shell section of the heat exchange assembly;

movable roller means interposed between the bundle and the base frame structure; and

a supporting framework for the base frame structure.

6. Force application apparatus for movement of a first article with respect to a second article, the apparatus comprising:

a frame having leading and trailing ends and being secured to the second article adjacent the leading end;

movable skid means on the frame, having depending dog means thereon, the skid means being connected to the first article;

the frame having a series of members thereon engaged by the dog means of the skid to prevent movement of the skid means in one direction;

means for application of force to the skid means to institute movement of the skid means in a direction opposite to that restrained by the engagement of the dog means on the members of the series;

the frame being elongated and including side members and transverse members;

said series of members being located on the transverse members;

the skid means being engaged on the side members; and

the series of members being engaged in end-to-end sequence by the dog means.

7. The invention of claim 6, and: manual control means for the dog means to place the dog means in operating and nonoperating positions. 

1. Means for placement and extraction of an element engaged within a shell and longitudinally slidably therefrom, the means comprising: an elongated frame having side members and having spaced apart transverse members spanning the side members; a skid, including plate means slidably engaged on the side members above the transverse members; block means on the transverse members; cylinder means, including a fixed actuating tube on the plate and a rod extendible and retractable from the tube, the rod being connected to the elements; two sets of dog means secured to the plate on the skid, the sets being individually movable from storage positions to use positions, each set being engageable with the block means when in its use positions; and means securing the frame to the shell whereby extension of the rod causes movement of the skid and the attached element outwardly from the shell when a first selected set of dogs is in use position, and causes movement of the elements into the shell when the other set of dogs is in use position.
 2. The invention of claim 1, wherein: the dogs contact the block means in end-to-end sequence.
 3. The invention of claim 2, wherein: the means securing the frame to the shell comprises clamping plates and hydraulic cylinder means controlling the clamping plates.
 4. The invention of claim 3, and: leveling rods extending upwardly from the frame and secured to the shell.
 5. Apparatus for removal and replacement of tube bundles in heat exchange assemblies, the tube bundles having a projecting portion and the assembly including a shell section, the apparatus comprising: a base frame structure including elongated side support beams, and intermediate support beams, and transverse structural meMbers interconnecting the side support beams and the intermediate support beam; the side support beam occupying a horizontal plane elevated with respect to a horizontal plane occupied by the intermediate support beam; block means on the transverse structural members; a skid assembly, including a plate member spanning the frame structure and having side rollers engaged on the side support beams, the plate member having an assembly depending therefrom to straddle the intermediate support beams; retractable and extendible dog means on the assembly, extending from the plate member, engageable with the block means when in extended position to prevent movement of the skid assembly in direction; extendible and retractable cylinder means having a fixed portion secured on the plate member and having a rod portion operatively connected thereto, the rod portion having means on one end for connection to the projecting portion of the bundle; clamping means securing the base frame structure to the shell section of the heat exchange assembly; movable roller means interposed between the bundle and the base frame structure; and a supporting framework for the base frame structure.
 6. Force application apparatus for movement of a first article with respect to a second article, the apparatus comprising: a frame having leading and trailing ends and being secured to the second article adjacent the leading end; movable skid means on the frame, having depending dog means thereon, the skid means being connected to the first article; the frame having a series of members thereon engaged by the dog means of the skid to prevent movement of the skid means in one direction; means for application of force to the skid means to institute movement of the skid means in a direction opposite to that restrained by the engagement of the dog means on the members of the series; the frame being elongated and including side members and transverse members; said series of members being located on the transverse members; the skid means being engaged on the side members; and the series of members being engaged in end-to-end sequence by the dog means.
 7. The invention of claim 6, and: manual control means for the dog means to place the dog means in operating and nonoperating positions. 